By Stephen Leahy

Coral reefs face certain extinction in a few decades unless there are unprecedented reductions in carbon emissions, leading Australian scientists warn.

Corals around the world may be nothing but rubble before a child born today turns 30 years old, and almost certainly before they’re 50.

The reason? Rising carbon dioxide (CO2) levels in the atmosphere are turning the oceans acidic far faster than previously observed.

“It isn’t just the coral reefs which are affected. A large part of the plankton in the Southern Ocean, the coccolithophorids, are also affected,” said Malcolm McCulloch, an environmental research scientist at the Australian National University in Canberra.

“These (coccolithophorids) drive ocean productivity and are the base of the food web which supports krill, whales, tuna and our fisheries,” McCulloch said in a statement.

Plankton also play a vital role in removing carbon dioxide from the atmosphere and sequestering it in the deep ocean. Major declines in plankton mean atmospheric CO2 levels would rise far faster than the present forecasts and oceans would become even more acidic.

Recent research is showing that the ocean has become about one-third of a pH unit more acid over the past 50 years. This is roughly triple previous measurements.

“This is still early days for the research, and the trend is not uniform, but it certainly looks as if marine acidity is building up,” said McCulloch.

The oceans and the atmosphere are intimately connected — the quintessential yin and yang.

Changes in the atmosphere affect the oceans and vice-versa. Pump extra CO2 into the atmosphere from burning fossil fuels and some of that extra CO2 combines with carbonate ions in seawater, forming carbonic acid. The fact that CO2 is making the oceans more acid was established just three years ago. Scientists are still scrambling to determine the overall impacts.

“Ocean acidification due to increased atmospheric CO2 is accelerating…Reducing CO2 emissions is the only way to prevent further damage to coral reefs,” they warn.

As carbon dioxide increases in the atmosphere, the concentration of carbonate ions declines, with the result that corals can no longer build reefs. The oceans have already absorbed nearly half of the fossil-fuel CO2 emitted into the atmosphere since pre-industrial times, causing a significant reduction in seawater pH.

“And with no reef framework, the habitat for an estimated million species is destroyed,” Hoegh-Guldberg said.

Ggood story, sad story. All the more sad as scinentists have recently discovered that coral have a kind of light-sensitive “eyesight” that allows them to “see” the full moon in spring/summer when they get ready to spawn, and they have been doing it — called on of the Earth’s most massive spawning events — for millions, billions of years, and now it might come to this……50 years down the road. Ouch!

An international team of Australian and Israeli researchers has
discovered what could be the aphrodisiac for the biggest moonlight sex
event on Earth.

An ancient light-sensitive gene has been isolated by researchers from
the ARC Centre of Excellence for Coral Reef Studies (CoECRS) that
appears to act as a trigger for the annual mass spawning of corals
across a third of a million square kilometres of Australia Great
Barrier Reef, shortly after a full moon.

The genes, known as a cryptochromes, occur in corals, insects, fish
and mammals – including humans – and are primitive light-sensing
pigment mechanisms which predate the evolution of eyes.

In a new paper published in the international journal Science,
the team, headed by Marie Curie Scholar Dr Oren Levy of CoECRS and the
University of Queensland, reports its discovery that the Cry2 gene,
stimulated by the faint blue light of the full moon, appears to play a
central role in triggering the mass coral spawning event, one of
nature’s wonders.

Professor Ove Hoegh-Guldberg, who leads the University of Queensland
laboratory in which the genes were discovered, said ”This is the key to
one of the central mysteries of coral reefs. We have always wondered
how corals without eyes can detect moonlight and get the precise hour
of the right couple of days each year to spawn.”